Many display applications may be connected via an associated data link or “data bus” to facilitate networked communication. In some data bus connections, an optical fiber data link may be used as the hardware layer to provide this communication medium between applications. For example, a Display Processing Computer (DPC) may provide a signal and transmit the signal to an adaptive flight display (AFD) device capable of displaying an image associated with the signal.
The quality of the optical fiber data link signal may degrade due to a number of causes including a fault at the source, a fault at the receiver and a fault with the optical fiber. Before signal quality degradation to a level of system failure, an operator may desire a signal quality measurement before an operation is cancelled or delayed due to surprise system failure.
The quality of this optical data link may be a valuable tool in early diagnosis of an increasing fault. Optical fiber data link signal quality status may be a helpful tool in preferred early diagnosis of an insidious data link problem before the insidious problem may degrade to a system failure. For example, fine dust may migrate into optical link interface between a cable and a display, reducing signal quality to a level that may degrade the ability of the display to properly function.
An unplanned data link outage may result in maintenance delays and ultimately, loss of valuable time of operation. For example, an unplanned data link outage in an aircraft display may result in unplanned maintenance activity to return the aircraft to active service, causing delays or cancellations of scheduled operations. Unplanned maintenance may also be ultimately more expensive than preventative maintenance.
In practice, operators may attempt to clean contact points of the optical data link physical layer to avoid physical signal degradation. For example, maintenance personnel may swab, with a cleaning solution, the connection points of optical fiber hardware in order to clean any debris from the fiber before reconnection. While helpful, this practice may only attempt to prevent a signal degradation of the physical layer.
Several approaches based on power measurement of the optical signal have been proposed but have found limited success. Most have marginal effectiveness from limitations in capabilities and/or application. For example, one shortfall of a power measurement scheme is a difficulty to measure power accurately with changing temperature. With a variable temperature, signal power may not be an accurate measurement of signal quality.
Consequently, a need exists for a system and method for accurate optical data link signal measurement enabling an operator to diagnose signal degradation before the degradation rises to a system failure.